Energy technology最新文献

Phase change materials (PCMs) provide advantages such as high energy storage density and passive operation for battery thermal management systems (BTMS). However, they face significant limitations under high discharge rates and thermal runaway scenarios, including inadequate temperature control duration and an inability to suppress thermal runaway propagation. To address these challenges, this study proposes a novel BTMS that integrates an annular thermoelectric cooler (ATEC) into a PCM-based system. The annular geometry of the ATEC facilitates easier integration compared to conventional flat-plate designs. Key findings include: (1) The ATEC achieves peak cooling performance with an optimal geometry (leg length = 1.2 mm, circumferential angle = 8°, thickness = 1.2 mm), exhibiting minimal performance degradation under varying thermal loads; (2) the integration of six fins within the system optimizes heat transfer and temperature uniformity; and (3) applying a 3 A current to the ATEC effectively maintains the battery temperature below 45°C under high discharge rates while maximizing PCM utilization. Crucially, during thermal runaway events, the proposed ATEC–PCM–BTMS operating at 3 A not only suppresses propagation effectively but also maintainsa high coefficient of performance.

With the increasing global demand for clean energy, aqueous zinc-ion batteries have emerged as a promising candidate for large-scale energy storage owing to their high safety, low cost, and environmental friendliness. However, challenges associated with zinc metal anodes, such as dendrite formation, hydrogen evolution reactions, and corrosion, significantly hinder their cycling stability and commercial viability. This review systematically summarizes eight functional strategies involving artificial interfacial layers to address these issues. This review provides a systematic summary of eight functional strategies based on artificial interfacial layers designed to overcome these issues. By analyzing the mechanisms of various interfacial materials, it highlights their effectiveness in suppressing dendrite growth, mitigating side reactions, and enhancing cycling performance, and further offers perspectives and recommendations for the rational design of highly reversible zinc anodes.

Charge storage by oxide anion intercalation into oxide materials has been recently demonstrated. In an effort to further expand this field beyond 3D systems, we have investigated this effect in quasi-2D oxides LaSrCu_0.5Mn_0.5O₄ and LaSrZn_0.5Mn_0.5O₄. The structure of these materials consists of octahedral (Cu/Mn)O₆ or (Zn/Mn)O₆ units, forming 2-dimensional layers, while La/Sr are located in the gaps between those layers. The spaces within the structure are expected to support the intercalation of the oxide anion. We first undertook half-cell measurements in a three-electrode setup and analyzed the contributions from capacitive and diffusive processes to the observed current in electrochemical measurements. We then assembled symmetric full cells using these materials and conducted galvanostatic charge–discharge studies, which showed greater pseudocapacitive properties for LaSrCu_0.5Mn_0.5O₄ compared to LaSrZn_0.5Mn_0.5O₄. Considering that the two materials are isostructural, a correlation between pseudocapacitive activity and charge transfer resistance was demonstrated. The energy density obtained from the symmetric cell of LaSrCu_0.5Mn_0.5O₄ was superior to that of LaSrZn_0.5Mn_0.5O₄, as well as those reported for several previously studied systems that operate based on oxide anion intercalation. In addition, symmetric cells of both materials were tested for at least 6000 cycles to examine the stability of these materials.

This study presents a novel thermal management approach for hybrid photovoltaic-thermal (PVT) solar panels using phase change materials (PCMs) to enhance energy efficiency in industrial applications such as food processing, textiles, and chemicals. The research develops an adaptive system that integrates paraffin wax-based PCMs infused with graphene to regulate panel temperature, improving both electrical and thermal performance. Paraffin waxes with phase change temperatures between 40 °C and 70 °C and latent heat capacities of 150–200 kJ kg⁻¹ were selected for their thermal stability, conductivity, and low cost. Laboratory and field tests evaluated various PCM formulations and configurations under controlled and real-world conditions. Key metrics, including temperature stability, electrical output, and thermal efficiency, were monitored using sensors and data loggers. Compared to conventional PVT systems, the PCM-enhanced panels demonstrated a 28% increase in thermal efficiency, a 15% rise in electrical output, and a 12 °C reduction in temperature fluctuation. These outcomes highlight the potential of PCM-integrated PVT panels to improve industrial energy efficiency and support sustainable operations.

This study employs an in-house CFD solver to simulate melting in single and dual phase change materials (PCMs) arrangements within a shell-and-tube heat exchanger for thermal energy storage via latent heat. Dual PCMs are configured radially and axially, with heat exchangers positioned horizontally, inclined, and vertically. Experiments on single PCM melting validate the simulation across different Reynolds numbers and PCM configurations. The research assesses thermal performance during transient melting, heat storage, and temperature uniformity, considering PCM type, configuration, orientation, and inlet temperature. Results show that conduction and convection modes in dual PCMs enhance heat transfer, with natural convection playing a key role. Dual PCM setups outperform single PCM, increasing energy storage by 15.5% and reducing outlet temperature fluctuations by 12.8%. The horizontally oriented radial dual PCM is the most efficient, improving natural convection and reducing melting time by 22.5% compared to single PCM. Higher inlet temperatures accelerate melting but decrease efficiency, emphasizing the importance of thermal matching. These insights support the development of energy-efficient PCM heat exchangers for solar thermal energy, waste heat recovery, and heating, ventilation, and air conditioning applications.

The working temperature of a cable is a key parameter for its current ampacity (load ampacity), and studying its performance is of great significance. This article aims to establish a steady-state thermal circuit model for multicircuit high-voltage cables. From the perspective of heat transfer, a heat transfer coupling method for multicircuit cables is proposed, and a steady-state thermal circuit model for multicircuit high-voltage cables considering current unbalance is constructed. First, by analyzing the heat transfer process of multicircuit high-voltage cables, a model indirectly coupled with walls is proposed to achieve rapid calculation of temperature distribution and current ampacity of trefoil arranged cables. Second, a method of independent modeling of each subcable is adopted to further improve the model functions, including temperature distribution calculation when the current distribution is uneven and calculation of cable temperature at different positions. Finally, the effectiveness of the model in calculating current ampacity and temperature distribution is demonstrated by building a 500 kV parallel cable experimental platform.

In pursuit of developing a suitable sodium-ion conducting solid polymer electrolyte (SPE) with enhanced ionic conductivity at room temperature (RT), poly(vinylidene fluoride) (PVDF) is blended with poly(ethylene oxide) (PEO) of varying molecular weights and sodium nitrate (NaNO₃) at different loadings, via the solution blending technique. The impact of the molecular weight of PEO on the ionic conductivity, dielectric properties, and structural evolution of PVDF-50 wt% PEO blend incorporated with y wt% NaNO₃ (y = 0,1,3,5,7,9,10,12,15), is studied in detail. Fourier transform infrared (FTIR) spectroscopy analysis confirms PEO–Na⁺ interaction in SPEs, while X-ray diffraction (XRD) and differential scanning calorimetry (DSC) analyses reveal suppressed PEO crystallinity, crucial for enhanced ion conduction. The highest ionic conductivity of 6.98 × 10⁻⁴ S cm⁻¹ at RT is achieved for PVDF-50 wt% PEO-9 wt% NaNO₃ with high molecular weight (HMW) PEO due to the availability of more coordinating sites. The mobility of mobile ions dominates the ionic conductivity in both HMW and low molecular weight (LMW) PEO-incorporated SPEs. The temperature-dependent conductivity studies reveal that both HMW and LMW PEO-incorporated SPEs follow Arrhenius behavior. The ion transference number, evaluated from the DC Wagner polarization method, is greater than or equal to 0.95 for selected SPEs.

Carbon dioxide heat pump is a very promising energy-saving technology. Based on the system parameters of the transcritical carbon dioxide heat pump cycle, this article has carried out 1D and 3D aerodynamic design of the compressor, and optimized the two-stage parameters respectively. The reliability of the model is verified by comparing the calculated results with the published experimental data. At the same time, the grid independence of the compressor calculation model is verified. By optimizing the blade parameters, the first-stage design efficiency is 78.8%, the second-stage design efficiency is 79.7%, and the final 3D calculation efficiency of the compressor is 79%. By comparing the 1D prediction results with the 3D numerical calculation results, the 1D prediction results of the total pressure ratio at different speeds are in good agreement with the 3D simulation values. 3D calculation results show that there is no obvious airflow separation in the compressor passage, the fluid flow is subsonic, and no obvious high Mach number flow is found in the impeller or diffuser, indicating that the throat will not be blocked. This study provides a reference for the design and optimization of a carbon dioxide compressor.

Heat dissipation of lithium-ion cells during its operation is critical for its performance. This study investigates the thermal behavior of a Li-ion battery module (7.8 Ah, 11.1 V) under varying discharge rates (C-rate) (0.91 to 1.45C) using experimental and numerical methods. Under natural convection at 1.45C C-rate and 27°C ambient temperature, the module reaches 55.2°C, exceeding safe operational limits. Forced convection (FC) with inlet velocities of 0.4 and 0.7 ms⁻¹ reduces the temperature to 40.8 and 37.7°C, respectively, though it causes temperature nonuniformity. To address these limitations, passive cooling with phase change material (PCM) was explored. PCM lowered the maximum temperature to 39.8°C with improved temperature uniformity (ΔT = 3.1°C). Further enhancement using expanded graphite increased PCM's thermal conductivity, maintaining low and uniform temperatures. Numerical simulations, validated against experimental results, were conducted to analyze heat transfer mechanisms under extreme C-rates up to 5C and hot ambient temperatures up to 45°C. The findings demonstrate that while FC effectively cools lithium-ion modules, it may reduce cell performance due to uneven temperature distribution. In contrast, PCM-based passive cooling offers better temperature uniformity, though it is limited by low thermal conductivity, which can be mitigated by incorporating EG.